GB795069A - Improvements in or relating to methods of sealing a tubular glass neck portion to a glass wall - Google Patents

Abstract

795,069. Welding, jointing and shaping glass ware. GENERAL ELECTRIC CO., Ltd. July 17, 1956 [Aug. 22, 1955], No. 24146/55. Class 56. [Also in Group XL(a)] In sealing a relatively thin walled tubular glass neck portion 8 to and so that it extends from an aperture in a relatively thick glass main-wall portion, such as a conical section 1 of a cathode ray tube, the neck portion 8 is supported coaxially with respect to, and spaced from, a circular hole 15 formed in the main wall portion 1 of greater diameter than the neck portion 8, the part of the main wall 1 adjacent the hole 15 and the nearer end of the neck portion 8 are heated, as by burners 16, so as to soften the glass, the neck portion 8 is fed axially towards the hole 15 against a flaring tool 9, Fig. 2, or 23, Fig. 4, which produces a flaring out 19 of the heat softened end, and the glass surrounding the hole 15 is squeezed between a pair of co-operating rollers 13, 17 or 22, 21 so as to reduce its thickness at the hole approximatley to that of the flared out portion 19, the movement of the neck portion 8 being continued to bring it into contact with the main wall 1 for effecting the sealing of the two portions together, the flaring tool 9 or 23 and rollers 13, 17 or 22, 21 being so arranged that the walls of the neck and main wall portions meet in substantially the same plane and merge smoothly without an abrupt change in wall thickness. As shown in Fig. 2, the conical section 1 is mounted on a horizontal face plate arranged to rotate about a vertical axis and having a central hole through which a support extends with an offset shaft on which a roller 6 is freely rotatable and with an arm 12 carrying the roller 13 freely rotatable about a shaft 14. The roller 6 is formed with a cylindrical part 7 to extend into the tubular neck portion 8, a flared portion 9 and a cut away part 10 into which the roller 13 extends to lie as close to the flare 9 as practicable. The roller 17, freely rotatable, is mounted so that the gap between the two rollers 13, 17 narrows towards the axis of the cone 1 and is slightly skew so that the glass is urged inwardly towards the neck 8. The neck 8 is rotated at the same angular velocity as the cone 1 and as the roller 17 is moved into engagement with the cone, the neck is lowered to the top of the flare 9 and then allowed to fall under its own weight till the flare 19 is met by the flattened glass of the cone, the pressure between the rollers 13, 17 being continued for a short while to seal the neck to the cone. The rollers are then removed and the structure annealed. The cathode ray tube is then completed in known manner. As shown in Fig. 4, the flaring tool 23 is combined with one roller 22 in a shaped roller 20 mounted on a shaft 24 extending from a support 25, the outer roller 21 being in the form of a truncated cone. Mounting and operation is similar to that of Fig. 2. The opening 15 of the cone 1 may be made by burning off the closed end of the cone after pressing and the size and shape is not critical.